I have started picking up this white arc in the center of images that seems to be more pronounced when taking shots over water. It happens in other shots against the sky but not as bad. Any ideas from anyone? This is a converted RAW image with no editing.

Caboose..... This was taken with a Canon 30D and Canon 400L 5.6, and I always use the built in lens hood. It is there with another lens...Sigma 70-200 2.8 EX I also use the petal lens hood that came withit.

Iput in a new CF and formatted it in the camera with same results. I was begining to think it was a problem with the 400L but not so sure, as I have a real hard time with getting a sharp image with either lens. Tripod and cable release give about same results as handheld.

You might have a light leak through the viewfinder... Do you wear glasses?
-> Try to repeat with the viewfinder shutter closed instead

The film chamber should be all black as well - do you see any bright surface inside when the mirror is up? The lens mount can be a problem as well. I would try some black electrical tape around the lens/body contact to narrow this down

Thanks for the reply NHL. No I don't wear glasses....I guess you are referring to a reflection?

Lens mount...hmmn. A few days ago when I changed to a different lens and then a couple days later put the 400 5.6 back on, the first few shots were very satisfactory...would not complain about those. But now that you mention the lens mount, I always thought there was waytoo muchmovement/slack after the lens was attached. It does that with both of those.

I will try the electrical tape and see what happens. I doappreciate the ideas.